Prius tire balancing "steering by wire"

does anyone have experience with unbalanced tires driving the Prius at
about 100 km/h? Unbalanced tires with a car without steerings aids can
be feeled at the driving wheel. What about the Prius with "steering by
wire" and less mechanical contact?

"Herbert" <h.m.mueller2901@t-online.de> wrote in message
news:1163394112.356049.170180@m7g2000cwm.googlegroups.com...[color=blue]
> does anyone have experience with unbalanced tires driving the Prius at
> about 100 km/h? Unbalanced tires with a car without steerings aids can
> be feeled at the driving wheel. What about the Prius with "steering by
> wire" and less mechanical contact?[/color]

the prius does not steer by wire, there is electric power assistance

mrcheerful
. wrote:
[color=blue]
> the prius does not steer by wire, there is electric power assistance[/color]

AFAIK there are no steer-by-wire cars are there? it seems a safety
feature that should be left in - redundancy in case of total electronic
failure.

In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
[email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
[color=blue]
> does anyone have experience with unbalanced tires driving the
> Prius at about 100 km/h? [...][/color]

If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
that could be felt through the car body as a whole, especially on
a good road? The Prius is generally smooth-running, although its
suspension is quite firm, more EUian (and JPian?) than USian, and
might let you feel such movements. (AFAIK, the trade-off benefit
of firmer suspension is better road-holding. Have we an expert?)
--
Andrew Stephenson

Andrew Stephenson schrieb:
[color=blue]
> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>[color=green]
> > does anyone have experience with unbalanced tires driving the
> > Prius at about 100 km/h? [...][/color]
>
> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
> that could be felt through the car body as a whole, especially on
> a good road? The Prius is generally smooth-running, although its
> suspension is quite firm, more EUian (and JPian?) than USian, and
> might let you feel such movements. (AFAIK, the trade-off benefit
> of firmer suspension is better road-holding. Have we an expert?)
> --
> Andrew Stephenson[/color]

Hello Andrew
my question is when you have an unbalanced tire if one can feel it at
the steering wheel, since Prius has no mechanical contact with the
wheels, the Prius (and some other Toyota cars) use "steering by wire",
e.g. the steering wheel sensor drives an electric motor, hence there is
no mechanical contact to the front wheels.

"Herbert" <h.m.mueller2901@t-online.de> wrote in message
news:1163536420.771295.198400@e3g2000cwe.googlegroups.com...[color=blue]
>
> Andrew Stephenson schrieb:
>[color=green]
>> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
>> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>>[color=darkred]
>> > does anyone have experience with unbalanced tires driving the
>> > Prius at about 100 km/h? [...][/color]
>>
>> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
>> that could be felt through the car body as a whole, especially on
>> a good road? The Prius is generally smooth-running, although its
>> suspension is quite firm, more EUian (and JPian?) than USian, and
>> might let you feel such movements. (AFAIK, the trade-off benefit
>> of firmer suspension is better road-holding. Have we an expert?)
>> --
>> Andrew Stephenson[/color]
>
> Hello Andrew
> my question is when you have an unbalanced tire if one can feel it at
> the steering wheel, since Prius has no mechanical contact with the
> wheels, the Prius (and some other Toyota cars) use "steering by wire",
> e.g. the steering wheel sensor drives an electric motor, hence there is
> no mechanical contact to the front wheels.[/color]

Fly by wire aircraft use "stick shakers" to provide ersatz mechanical
feedback to the pilot. Unless the Prius were similarly equipped with a
mechanical device to provide steering feedback one would not feel the
shaking of an unbalanced tire... er, tyre <G> through the steering wheel.
It would, however, communicate vibration to the body through the suspension.

I doubt such a device exists on the Prius since some drivers have complained
about the lack of such feedback, e.g. "floaty" steering.
--
Mike Harris
Austin TX

"Herbert" <h.m.mueller2901@t-online.de> wrote in message
news:1163536420.771295.198400@e3g2000cwe.googlegroups.com...[color=blue]
>
> Andrew Stephenson schrieb:
>[color=green]
>> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
>> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>>[color=darkred]
>> > does anyone have experience with unbalanced tires driving the
>> > Prius at about 100 km/h? [...][/color]
>>
>> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
>> that could be felt through the car body as a whole, especially on
>> a good road? The Prius is generally smooth-running, although its
>> suspension is quite firm, more EUian (and JPian?) than USian, and
>> might let you feel such movements. (AFAIK, the trade-off benefit
>> of firmer suspension is better road-holding. Have we an expert?)
>> --
>> Andrew Stephenson[/color]
>
> Hello Andrew
> my question is when you have an unbalanced tire if one can feel it at
> the steering wheel, since Prius has no mechanical contact with the
> wheels, the Prius (and some other Toyota cars) use "steering by wire",
> e.g. the steering wheel sensor drives an electric motor, hence there is
> no mechanical contact to the front wheels.
>[/color]


I am pretty sure that Toyota does not currently produce any "steer by wire"
vehicles.

Note that "steer by wire" means that there is no mechanical connection
between the steering wheel and the steering rack, which is connected to the
front wheels.

Electric power steering (which the Prius and the 2007 LS 470 have) means
that the power steering pump is driven by an electric motor, not a
belt-driven pulley, but there is still a steering shaft connecting the
steering wheel to the steering rack. In the the Prius and 2007 LS, the
steering wheel is connected to a steering shaft which is connected to a
steering rack which is connected to the rack ends, which are connected to
the front wheels.
--

Ray O
(correct punctuation to reply)

Ummm... we prefer to be referred to as American...


Andrew Stephenson wrote:[color=blue]
> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>[color=green]
> > does anyone have experience with unbalanced tires driving the
> > Prius at about 100 km/h? [...][/color]
>
> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
> that could be felt through the car body as a whole, especially on
> a good road? The Prius is generally smooth-running, although its
> suspension is quite firm, more EUian (and JPian?) than USian, and
> might let you feel such movements. (AFAIK, the trade-off benefit
> of firmer suspension is better road-holding. Have we an expert?)
> --
> Andrew Stephenson[/color]

In article <1163536420.771295.198400@e3g2000cwe.googlegroups.com>
[email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
[color=blue]
> Andrew Stephenson schrieb:
>[color=green]
> > If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
> > that could be felt through the car body as a whole, especially on
> > a good road? The Prius is generally smooth-running, although its
> > suspension is quite firm, more EUian (and JPian?) than USian, and
> > might let you feel such movements. (AFAIK, the trade-off benefit
> > of firmer suspension is better road-holding. Have we an expert?)[/color]
>
> my question is when you have an unbalanced tire if one can feel it at
> the steering wheel, since Prius has no mechanical contact with the
> wheels, [...][/color]

As "mr cheerful" pointed out, the Prius _does_ have a mechanical
connection between the steering and road wheels. Power steering
simply reinforces the driver's efforts. If it fails, the driver
can still haul at the wheel and thus steer the car.

AFAIK, this arrangement is commonplace in modern cars.
--
Andrew Stephenson

In article <1163543283.526728.192130@k70g2000cwa.googlegroups.com>
[email]bogusmailmark@yahoo.com[/email] "Mark" writes:
[color=blue]
> Ummm... we prefer to be referred to as American...
>
> Andrew Stephenson wrote:[color=green]
> > In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
> > [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
> >[color=darkred]
> > > does anyone have experience with unbalanced tires driving the
> > > Prius at about 100 km/h? [...][/color]
> >
> > If a tyre was unbalanced, [...][/color][/color]

Even the top-posters? ;-) I shall, of course, go and eat worms.
--
Andrew Stephenson

"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
news:d182e$455a3405$44a4a10d$14214@msgid.meganewsservers.com...[color=blue]
>
> "Herbert" <h.m.mueller2901@t-online.de> wrote in message
> news:1163536420.771295.198400@e3g2000cwe.googlegroups.com...[color=green]
>>
>> Andrew Stephenson schrieb:
>>[color=darkred]
>>> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
>>> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>>>
>>> > does anyone have experience with unbalanced tires driving the
>>> > Prius at about 100 km/h? [...]
>>>
>>> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
>>> that could be felt through the car body as a whole, especially on
>>> a good road? The Prius is generally smooth-running, although its
>>> suspension is quite firm, more EUian (and JPian?) than USian, and
>>> might let you feel such movements. (AFAIK, the trade-off benefit
>>> of firmer suspension is better road-holding. Have we an expert?)
>>> --
>>> Andrew Stephenson[/color]
>>
>> Hello Andrew
>> my question is when you have an unbalanced tire if one can feel it at
>> the steering wheel, since Prius has no mechanical contact with the
>> wheels, the Prius (and some other Toyota cars) use "steering by wire",
>> e.g. the steering wheel sensor drives an electric motor, hence there is
>> no mechanical contact to the front wheels.
>>[/color]
>
>
> I am pretty sure that Toyota does not currently produce any "steer by
> wire" vehicles.
>
> Note that "steer by wire" means that there is no mechanical connection
> between the steering wheel and the steering rack, which is connected to
> the front wheels.
>
> Electric power steering (which the Prius and the 2007 LS 470 have) means
> that the power steering pump is driven by an electric motor, not a
> belt-driven pulley,[/color]

Does the Prius have a hydraulic pump? I used to own a Saturn Vue that had
"electric" power steering. There was no hydraulic pump. An electric motor
was connected directly to the sterring shaft and provided the assist. I
assume this is what the Prius does as well, but since I have not actually
wokred on a Prius, I can't be sure. The electric power sterring in the Vue
was mostly devoid of feel, but I got used to it. It wasn't nearly as dead
feeling as the power steering from a early 70's Chrysler product.
[color=blue]
> but there is still a steering shaft connecting the steering wheel to the
> steering rack. In the the Prius and 2007 LS, the steering wheel is
> connected to a steering shaft which is connected to a steering rack which
> is connected to the rack ends, which are connected to the front wheels.[/color]

My Saturn Vue was this way as well. It still had a conventional rack and
pinion steering system, the "electric" part was just an assist. This is not
a true fly by wire system. I do have three farm tractors that have "fly by
hydraulic" sterring systems. There is no mechnical link between the steering
wheel and the front wheels. The front wheels are moved solely by hydraulic
cylinders that are activated by steering wheel movement.
--
Regards,

Ed White
[url]http://home.mindspring.com/~ed_white/[/url] - my automotive opinions
[url]http://home.mindspring.com/~ed_white/id7.html[/url] - my oil filter comparison

"C. E. White" <cewhite3@removemindspring.com> wrote in message
news:455b289f@kcnews01...[color=blue]
> "Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message
> news:d182e$455a3405$44a4a10d$14214@msgid.meganewsservers.com...[color=green]
>>
>> "Herbert" <h.m.mueller2901@t-online.de> wrote in message
>> news:1163536420.771295.198400@e3g2000cwe.googlegroups.com...[color=darkred]
>>>
>>> Andrew Stephenson schrieb:
>>>
>>>> In article <1163394112.356049.170180@m7g2000cwm.googlegroups.com>
>>>> [email]h.m.mueller2901@t-online.de[/email] "Herbert" writes:
>>>>
>>>> > does anyone have experience with unbalanced tires driving the
>>>> > Prius at about 100 km/h? [...]
>>>>
>>>> If a tyre was unbalanced, at 100 Km/h wouldn't it produce a shake
>>>> that could be felt through the car body as a whole, especially on
>>>> a good road? The Prius is generally smooth-running, although its
>>>> suspension is quite firm, more EUian (and JPian?) than USian, and
>>>> might let you feel such movements. (AFAIK, the trade-off benefit
>>>> of firmer suspension is better road-holding. Have we an expert?)
>>>> --
>>>> Andrew Stephenson
>>>
>>> Hello Andrew
>>> my question is when you have an unbalanced tire if one can feel it at
>>> the steering wheel, since Prius has no mechanical contact with the
>>> wheels, the Prius (and some other Toyota cars) use "steering by wire",
>>> e.g. the steering wheel sensor drives an electric motor, hence there is
>>> no mechanical contact to the front wheels.
>>>[/color]
>>
>>
>> I am pretty sure that Toyota does not currently produce any "steer by
>> wire" vehicles.
>>
>> Note that "steer by wire" means that there is no mechanical connection
>> between the steering wheel and the steering rack, which is connected to
>> the front wheels.
>>
>> Electric power steering (which the Prius and the 2007 LS 470 have) means
>> that the power steering pump is driven by an electric motor, not a
>> belt-driven pulley,[/color]
>
> Does the Prius have a hydraulic pump? I used to own a Saturn Vue that had
> "electric" power steering. There was no hydraulic pump. An electric motor
> was connected directly to the sterring shaft and provided the assist. I
> assume this is what the Prius does as well, but since I have not actually
> wokred on a Prius, I can't be sure. The electric power sterring in the Vue
> was mostly devoid of feel, but I got used to it. It wasn't nearly as dead
> feeling as the power steering from a early 70's Chrysler product.[/color]

Good question, I do not know how the power steering in a Prius works. I had
assumed, perhaps incorrectly, that it had a hydraulic pump that was driven
by an electric motor, like the MR2 had. Perhaps someone with a Prius can
ansewer?
[color=blue]
>[color=green]
>> but there is still a steering shaft connecting the steering wheel to the
>> steering rack. In the the Prius and 2007 LS, the steering wheel is
>> connected to a steering shaft which is connected to a steering rack which
>> is connected to the rack ends, which are connected to the front wheels.[/color]
>
> My Saturn Vue was this way as well. It still had a conventional rack and
> pinion steering system, the "electric" part was just an assist. This is
> not a true fly by wire system. I do have three farm tractors that have
> "fly by hydraulic" sterring systems. There is no mechnical link between
> the steering wheel and the front wheels. The front wheels are moved solely
> by hydraulic cylinders that are activated by steering wheel movement.
> --
> Regards,
>[/color]

The hydraulic steering systems sound like the setup that some larger
forklifts have, where the hydrostatic drive pump also provides steering and
other duties.
--

Ray O
(correct punctuation to reply)

In article <455b289f@kcnews01>
[email]cewhite3@removemindspring.com[/email] "C. E. White" writes:
[color=blue]
> Does the Prius have a hydraulic pump? [...][/color]

AIUI Prius' steering servo is electric, as you speculate. There
may be a hydraulic component, as another post suggested. Toyota
do caution (in line with IIRC Ray's counsel) against holding the
wheel hard over for too long, lest it overheat things.

The steering itself is very gentle and easy. But the suspension
is, as I posted previously, "live" in the EUian/JPian manner and
transmits road bumpiness more than a USian-style car would.
--
Andrew Stephenson